The present invention relates to push bar exit devices for controlling ingress and egress, and more particularly to a tamper-resistant alarm to be employed in conjunction with such exit devices.
Emergency exit or panic bolt devices of the surface-mounted type are well known. These devices are mounted on the inner face of outwardly opening doors in public and commercial establishments where a number of strategically placed exits must afford quick exit without keys for the safety of personnel. One variety of these devices, the rim exit type, is exemplified by the apparatus disclosed in U.S. Pat. No. 3,877,262 to Williams, which is commonly assigned with the present patent application, and is herein incorporated by reference in its entirety. The Williams exit latch and actuator assembly includes a crossbar or push bar supported by parallel links which moves generally toward and away from the door, thereby permitting the user to retract a latch bolt by depressing the push bar.
Commonly assigned U.S. application Ser. No. 535,509, filed Sept. 26, 1983, discloses a door exit device of the push bar type having a streamlined design. This exit device incorporates a rear channel member having a latch bolt assembly at one end and a pair of spaced rails mounted thereto. The push bar extends outwardly of the channel member, with one or more links pivotally connected to the rails at one end for mounting the push bar in the channel.
Push bar emergency exit devices have in many cases incorporated an alarm which sounds locally or remotely, or both, when the push bar is depressed. This provides a valuable safeguard against clandestine exit by unauthorized personnel. It is appropriate that the alarm sound in most situations in which the panic bar is depressed, but it may be desirable to provide the facility for authorized personnel to override the alarm during ingress, or egress, or both.
Panic bar exit alarm apparatus which provides various modes of selective alarm actuation is disclosed in U.S. Pat. No. 4,006,471 to Pappas. The Pappas exit lock system incorporates an alarm assembly which is integrally manufactured with other components of the device. Many of the internal parts of this assembly are mounted directly to the back plate of the device and remain bolted to the door when the alarm housing, which is hinged to the back plate, is removed. A key and control cam mechanism is required to unhinge the alarm housing and gain access to the alarm components. This system is obviously incompatible with prior rim exit apparatus and does not permit retrofitting of a separate alarm module.
Accordingly, it is a primary object of the invention to provide an improved push bar type exit device incorporating an alarm. It is advantageous to provide an alarm in the form of a modular assembly, which may be retrofitted to preexisting rim exit devices and the like.
Another object of the invention is that such devices provide security against clandestine tampering with the alarm components. The improved exit device of the invention should facilitate access to internal alarm mechanisms by authorized personnel, yet protect against unauthorized access to such mechanisms.
A further object is to achieve a secure exit alarm device in a variety of configurations. As a related objective, it is desirable to provide a streamlined exit device which incorporates a temporary alarm without detracting from the compactness and mechanical efficiency of the device.